1. What is BMI?

Body Mass Index (BMI) is a measure that uses height and weight to work out if weight is healthy. For children and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

• \( weight \) — Body weight in kilograms
• \( height \) — Height in meters

Note: For children, the BMI number is plotted on growth charts to determine the BMI-for-age percentile.

3. Importance of BMI Calculation for Children

Details: BMI-for-age is the recommended measure for screening overweight and obesity in children aged 2-18 years. It accounts for normal differences in body fat between boys and girls and differences in body fat at various ages.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, age in years (2-18), and select gender. For accurate results, measurements should be taken with minimal clothing.

5. Frequently Asked Questions (FAQ)

Q1: Why is BMI different for children than adults?
A: Children's body composition varies as they grow, and differs between boys and girls. BMI-for-age accounts for these differences.

Q2: What is a healthy BMI for a child?
A: Healthy weight is between the 5th and 85th percentiles on growth charts. However, interpretation should be done by a healthcare professional.

Q3: When should BMI be measured in children?
A: The UK National Childhood Measurement Programme measures children in Reception (age 4-5) and Year 6 (age 10-11).

Q4: Are there limitations to BMI for children?
A: BMI doesn't distinguish between fat and muscle. Athletic children may have high BMI due to muscle rather than fat.

Q5: Where can I find UK growth charts?
A: The UK-WHO growth charts are available from the Royal College of Paediatrics and Child Health website.